WO2007150078A2

WO2007150078A2 - Mining skip

Info

Publication number: WO2007150078A2
Application number: PCT/ZA2006/000124
Authority: WO
Inventors: Berend Jan Werkman
Original assignee: Berend Jan Werkman
Priority date: 2005-10-31
Filing date: 2006-10-30
Publication date: 2007-12-27
Also published as: WO2007150078A3

Abstract

A particulate material load carrier in the form of a mining skip 10 comprises an ore carrying chamber 12 extending within a rectangularly overhead profiled outer shell 14 that is formed with charging and discharge apertures 16 and 18 respectively while the wall of the shell 14 is of undulating pattern in presenting a corrugated patterning. The shell 14 consists of a core part 12 of which the corrugated patterning extends circumferentially about the central axis 22 of the skip 10 along planarly extending shell walls 26 and through arcuate corners 28 and a discharge chute 30. The core part 20 is formed from a plurality of stackably secured shell sections.

Description

(1) TITLE OF THE INVENTION MINING SKIP

(2) BACKGROUND TO THE INVENTION

The mass of mining skips is of critical importance as the load that such skips can carry depends on such mass. One way of reducing their mass is to reduce skip wall thickness. This however has a serviceability limitation in that the skip must maintain the required clearances in the shaft when put under load, and withstands repeated flexing on loading and discharging. A more lightweight skip structure of conventional wear-resistant material that ^• retains the required structural strength will consequently be of substantial benefit. It is, amongst others, an object of this invention to reduce skip mass while still retaining skip strength and serviceability.

(3) FIELD OF THE INVENTION

This invention relates to a particulate material load container adapted for moving ore type loads or the like along a shaft along which it runs once operatively installed in such case serving as load carrier. While not so limited the container finds particular useful application when in the form of a mining skip for moving ore type loads along a shaft along which it runs once operatively installed though it can in the appropriate case also be used as loading flask.

(4) PRIOR ART DESCRIPTION Skips known to the applicant are formed with planar shell walls of which the wall width requires a certain thickness and external and internal reinforcing to ensure that such skips retain the required skip strength. The internal reinforcing is often in the shape of cascades that are downwardly inclined at an angle of between 45 and 60 degrees from the horizontal. The bodies of such skips provide their structural integrity while wear liners fitted along their inside surfaces protect the bodies against wear brought about by the handling of ore that in particular takes place during skip charging and discharging. The protective lining protects the skip body but unfortunate also contributes to the mass of such skips. The hoisting and lowering gear of a skip inclusive of the rope, from which it depends, however, limits the total mass that can be suspended in turn affecting the size of its payload. A reduction in skip mass is naturally under all circumstances beneficial but is particularly useful in the case of existing mineshafts where the mine capacity can be increased by expanded underground operations but is limited by the hoisting capacity. (5) BRIEF DESCRIPTION OF THE DRAWING

The invention is now described, by way of example, with reference to the accompanying drawings. In the drawings

Figure 1 shows a container, according to the invention, in the form of a mining skip, in isometric discharge opening facing view,

Figure 2 shows the skip in isometric view from the opposite side to that of figure 1 ,

Figure 3 shows in isometric view a shell section of which a plurality are stackably inter- securable into forming the fixed cross sectional part of the shell,

Figure 4 shows in isometric detail the strengthening of a curved shell section corner representing part of a shell wall and the sloping of shell wall corrugations,

Figure 5 shows in detail the overlapping positioning of shell sections in their stackable inter- securing, and

Figure 6 shows the corrugated patterning of the outlet chute of the skip.

(6) DETAILED DESCRIPTION OF THE DRAWINGS Referring to figures 1 and 2 of the drawings a particulate material load container, according to the invention, in the form of a mining skip is generally indicated by reference numeral 10.

The skip 10 comprises an ore carrying chamber 12 extending within a rectangularly overhead profiled outer shell 14 that is formed with charging and discharge apertures 16 and 18 respectively while the wall of the shell 14 is of undulating pattern in presenting a corrugated patterning. The shell 14 consists of a core part 20 of which the corrugated patterning extends circumferentially about the central axis 22 of the skip 10 along planarly extending shell walls 26 and through arcuate corners 28 and a discharge chute part 30 as discussed in more detail below.

The skip 10 being conventionally constituted for mining shaft operations, is fitted with conventional coupling means in the form of a hoisting cable coupling formation 32 fitted to an overhead transom 34 situated at the upper end of stringers 36 extending adjacent the shell 14 along which rail engaging roller clusters (not shown) are spaced for guiding the skip along rails extending along opposite walls of a shaft as forming the skip path. The discharge aperture 18 for the chamber 12 is conventionally reopenably closable by way of a closure in the form of a swivelably mounted door 38. Instead of roller clusters the skip can naturally also make use of guide ropes (not shown). In also referring to figure 4 and to strengthen the shell 14 against deformation once the skip is under load the corners 28 are fitted with reinforcing elements in the form of reinforcing pads 40 that are snugly secured along the recessed sections 42 of the corrugations through the corners 28. The pads 40 are formed with curved central sections 44 extending at opposite ends into linear end sections 46 to give a proper strengthening effect. The pads 40 are typically welded or bolted to the shell 14.

While staying with figure 4 and while the shell 14 is used as such as skip body without any lining the inside surface of the shell 14 is directly exposed to wear during contact with ore, particularly during charging and discharging of the skip 10 during use. This is particularly relevant for the chamber charging opening facing circumferentially extending oblique shell wall webs 48 of the corrugations webbing inner and outer planar areas 50 and 52. The shell wall is formed to cause the webs 48 to stand in a particulate material roll-promoting slope for smaller particles forming part of run of mine ore relative to the axis 22 of the skip 10, to mitigate an abrasion creating sliding contact effect during chamber charging and discharging. This promotes the rolling of smaller ore particles coming into contact with the shell 14. The angle of the slope of the webs 48 is related to the angle 54 defined between the plane through the webs 48 and the radial direction from the central axis 22 of the skip 10 by being its resultant in relation to a right angle.

To find the optimum angle 54 the inventor has carried out a number of trials and experiments. It must be borne in mind that the object of the invention is to provide a skip that weighs less than conventional skips but still maintains adequate structural strength to be used for run of mine ore consequently containing a variety of particle sizes. Impact tests against an inclined member have been carried out by the inventor using different sizes of particles selected from typical run of mine rock fragments. The angle and velocity of the particle body flowing from the typical discharge chute were used and the slope of the inclined body was varied. The impact was recorded on high-speed video camera, while the forces caused by the impact were simultaneously recorded by means of strain gauges and very high frequency recording and computing equipment.

The inventor has surprisingly found that a steeper incline angle, though up to a limit, results in less wear. More particularly, it was found that wear is minimised at an incline slope that corresponds with an angle 54 of between 60 and 85 degrees with an optimum angle of 78 degrees, thus a slope of 12 degrees. It has been found that an increase of the slope has the effect of changing the nature of particle impact from a rolling and bouncing action to a partially sliding and rolling action. The impact forces were found to be substantially lower with a sliding effect. The inventor has also found that the direction of particle rolling changed when sliding occurred but that the preferred slope nevertheless induced a particle rolling action. During the tests, the sliding contact of individual particles was also observed to cause more wear than their rolling contact. It was however surprisingly found that the smaller particles maintained their bouncing and rolling action at the steeper slope in contrast with the larger particles.

The rationale behind the phenomenon of the observed lower wear at a steeper incline angle is submitted to be the fact that only a small proportion of the particles in run of mine ore are large with smaller particles thus forming the bulk of the ore. The smaller particles will therefore roll and bounce off the webs 48 at the identified impingement angle, consequently causing little wear while the sliding wear of the larger particles does not significantly contribute to wear owing to forming a substantially smaller fraction of the ore body. It was also found that a slope of 12 degrees had the added advantage of reducing impact loads experienced by the wall of the skip 10. The tests further showed that in a skip 10 of which the slope of the webs 48 was at the optimum angle the smaller particles would bounce off the wall on impact and rotate. Their rotation in a downward directed stream of particles was found to cause the body of particles to impact and rub against each other as well as against the webs 48 lower down in the skip, thereby slowing down the speed of the particle flow resulting in reducing skip wear. The rolling action induced on the larger particles by the optimum web slope similarly caused their retardation even though their rotation was in an opposite direction to that of the smaller particles.

In addition to a steep web slope the pitch of the corrugations is selected to be in the order of the average ore particle size thus promoting an ore particle rolling effect. In referring to figures 3 and 4 in addition to figures 1 and 2, the core part 20 is formed from a plurality of shell sections 56, as shown in figure 3. Each shell section 56 is manufactured from generally planar sidewall forming sections 60 linked together by corner sections 62 by welding or otherwise. As also shown in figure 4 the corner sections 62 of each shell section 56 extends into opposite linear end sub-sections 64 of which the lengths are pre-determined to result in the locations of securing 66 between the corner sections 62 and the side wall forming sections 60 being along the regions of contra flexure of the wall of the shell 14. Owing to the shell 14 being in the form of sections 56 this enables replacement of worn shell parts without requiring full shell overhaul or even discarding. In forming the core part 20 successive shell sections 56 are stackably secured. As shown in figure 5 this is achieved via matchingly formed overlapping circumferential end lips 68 of the respective shell sections 56. Once stackably combined the contiguous sidewall forming sections 60 form the shell walls 26 and the contiguous corner sections 62 the arcuate shell corners 28.

As shown in figures 1 , 2 and 6 the discharge chute 30, as ending in the discharge aperture 18, is bordered by a sloped floor in the form of an obliquely extending wall 70 that integrally extends into chute sidewalls 72. The border of the chute 30 as formed by the walls 70 and 72 is also corrugatedly formed with the corrugations there along, however, extending oblique to the central axis 22 of the skip 10.

The skip 10 is naturally manufactured from hardwearing material to withstand ore charging and discharging abrasion. The additional strength given to the shell 14 by the corrugations, however, enables the wall thickness of the shell to be less than what it would have been when conventionally purely planarly formed. This in turn results in a more lightweight shell than the conventional giving the skip a larger ore handling capacity.

While the container is adapted to serve as skip 10, thus intended for moving loads along a shaft according to the description above, it can also be adapted for other functional use such as for simply handling run of the mine ore or other particular material loads. The container according to the skip configuration as described can, for example, also be used as measuring flask for pre-measuring amounts of ore that is thus charged to a skip. It is in fact common practise to use such containers underground in mining operation to prevent skip overloading. It can even be adapted for use in transporting loads of particulate material between locations.

Claims

(7) CLAIMS

(1 ) A particulate material load container (10) adapted for handling loads having a particulate material size distribution typical of run of mine type ore comprising an material type load containing chamber (12) extending within an outer shell (14) of which at least the largest part of the length of the shell (14) extends at a fixed cross sectional area between container charging and discharge apertures (16, 18) at least the latter of which is openable by way of a reopenable closure (38); characterised in that at least the largest part of the shell (14) in both its circumferential and axial directions is of regular extending undulating pattern of which the direction of undulation extends about the central axis (22) of the load container (10) and which undulations are profiled and extending to a suitable extent to enable the thickness of the shell wall to be reduced as compared to a smoothly walled shell (14) of similar strength as brought about by the structural strength against outward shell wall displacement, as arising once the container (10) is under load, imparted by the undulations, with the shell being of suitable hard wearing material to withstand the abrasion effect of ore charging and discharging, the container (10) when being transportable by mean of equipment that involves container suspension being fitted with coupling means (32) enabling its coupling to container handling equipment.

(2) A particulate material load container (10) as claimed in claim 1 in which the shell (12) is at least constituted from walls (26) that extend generally planarly bearing the undulations in mind, defining its core part (20) in the case of its being more extensive.

(3) A particulate material load container (10) as claimed in claim 2 in which the shell (14) also extends through arcuate corners (28) linking the planarly extending shell walls (26).

(4) A particulate material load container (10) as claimed in claim 3 in which the shell (14) extends fully circumferentially undulatingly about the central axis (22) of the container and consequently also through its corners (28).

(5) A particulate material load container (10) as claimed in claim 4 in which arcuate corners (28) are fitted with reinforcing elements (40) following adjacent recess zones (42) defined along the undulations in the wall of the shell (14).

(6) A particulate material load container (10) as claimed in claim 5 in which the reinforcing elements are in the form of reinforcing pads (40). (7) A particulate material load container (10) as claimed in any one of the preceding claims in which the undulating pattern of the shell (14) is in the form of generally corrugated patterning.

(8) A particulate material load container (10) as claimed in claim 7 in which at least the chamber charging aperture facing circumferentially extending oblique shell wall webs (48) extending along the inner surfaces of the corrugations along the shell (14) stand in a particulate material roll promoting and thus abrasion mitigating slope, at least for smaller particles forming part of a material charge, relative to the axis (22) of the container.

(9) A particulate material load container (10) as claimed in claim 8 in which the slope is in the order of between 5 and 30 degrees as corresponding with an angle size of between 85 and

60 degrees for an angle (54) formed between the planes of the webs (48) as intersecting planes extending radially outward from the axis (22) of the container.

(10) A particulate material load container (10) as claimed in claim 9 in which the slope is 12 degrees as corresponding with an angle size of 78 degrees for the angle (54). (11 ) A particulate material load container (10) as claimed in any one of the preceding claims of which at least the largest part of the fixed cross section extending part of the shell (14) is constituted from a plurality of pre-manufactured shell sections (56) that are stackably secured to one another along facing edges.

(12) A particulate material load container (10) as claimed in claim 11 in which opposite edge regions (68) of each shell section (56) are arranged to enable an overlap securing between adjacent shell sections (56).

(13) A particulate material load container (10) as claimed in claim 11 or claim 12 in which the shell sections (56), in the case of their presenting arcuately linked linear sided end profiles, is each manufactured from the relevant number of undulatingy patterned planar sections (60) joined by matchingly undulatingy patterned curved corner sections (62).

(14) A particulate material load container (10) as claimed in claim 13 in which each corner section (62) extends into opposite linear end sub-sections (64) along the opposite ends of which the planar sections (60) are secured into forming the shell sections (56), the lengths of the linear sub-sections (64) along the circumferential direction of the shell sections (56) in conjunction with the planar sections (60) being selected to result in their locations of inter securing (66) being at least substantially along the zones of contra flexure of the shell (14). (15) A particulate material load container (10) as claimed in any one of the preceding claims of which the shell (14) is of at least generally rectangular end profile.

(16) A particulate material load container (10) as claimed in claim in any one of the preceding claims that is formed with a discharge chute (30) extending along a sloped floor (70) in relation to the axis (22) of the container (10) ending in the discharge aperture (18).

(17) A particulate material load container (10) as claimed in claim 16 in which at least the sloped floor (70) of the chute is undulatingly if not corrugatedly formed.

(18) A particulate material load container (10) as claimed in any one of the preceding claims in which the shell (14) is profiled to effectively fit a mining shaft defining a path of displacement of the container along which it is intended to run once in operative use, the coupling means (32), with the container (10) as thus fitted, being arranged to enable the coupling of the container (10), as being in the form of a mining skip, to a mine hoisting facility while the shell (14) is otherwise arranged to promote its effective displacement along such , path.